Industrial electronic hardware equipment has typically been designed to allow easy access to the electronic components contained inside the chassis for testing, repair, and replacement purposes. It is desirable that individual electronic circuit cards be easily installed and removed. Securing electronic circuit cards inside the chassis and allowing easy installation and removal is accomplished by attaching plastic guides to the interior of the chassis. The plastic guides are typically used in pairs and are affixed to opposite sides of a chassis facing each other. The plastic guides are grooved so that opposite edges of an electronic circuit card may be inserted into the groves and become seated securely between the opposing pairs of plastic guides. The plastic guides may be attached to a chassis with the grooves oriented horizontally or vertically. A single plastic guide may also be used to secure one edge of an electronic circuit card. The other edge may be secured in some other fashion. For example, a single plastic guide may be used in conjunction with an expansion slot bracket found in many personal computers which is screwed into the back of the frame of the chassis. Additionally, plastic guides may be used to hold a metal plate or tray which in turn holds an electronic circuit card.
Plastic guides have been made in various sizes and shapes depending upon chassis location and orientation required to receive an edge of an electronic circuit card. Various approaches have been utilized in attaching plastic guides to a chassis. One approach utilizes a rivet-on plastic guide. This requires a rivet part and access to the exterior surfaces of the chassis for installation purposes. The rivets protrude from the exterior surfaces of the chassis and thus require clearances around the exterior of the chassis. These rivet protrusions can be scraped, bumped, or caught on objects brought near the vicinity of the exterior of the chassis. This may cause the rivets to break and the plastic guide to become unsecured from the chassis. Additionally, the stress in the rivets over time may cause cracking of the plastic resulting in breakage, thus causing the plastic guide to become unsecured from the chassis. Replacing a rivet-on plastic guide that has failed is difficult due to the chassis being full of electronic components and the access to the exterior surfaces of the chassis required to use the rivet tool. Also, if a rivet-on plastic guide needs to be removed for some reason, the rivet connection must be severed or broken. Once removed, the plastic guide is not reusable.
Another approach uses a snap-on plastic guide. Typically the plastic guide has one or more protrusions on its surface that are forced through openings in the chassis. These protrusions are designed so that they either expand after insertion or have an initial larger diameter portion than the opening they have been forced through, thus securing the plastic guide piece to the chassis. This functional approach, however, makes it difficult to remove the plastic guide once it has been snapped into place. Once removed, the plastic guide may be so damaged that it may not be reusable and another plastic guide must be used in its place. Additionally, the protrusions through the surface require clearances on the outside surfaces of the chassis, making them susceptible to the same breakage problems associated with rivet-on plastic guides.
An additional approach utilizes a plastic guide piece with a "T" shaped protrusion that engages a keyhole type slot in the chassis. The top of the "T" inserts in the slot. The guide is then moved laterally engaging one arm of the "T" over the outer surface of the chassis, preventing the plastic guide from moving perpendicular to the chassis surface. In some instances the plastic guide may also have a bump or other protrusion that engages or snaps into a hole or some other detail to prevent movement of the plastic guide in a direction parallel to the chassis surface.
In some instances, rivet-on, snap-on, or keyhole type plastic guides are not practical because of the shape of the chassis and required orientation of the plastic guides, such as in a corner offset. In such cases, protrusions through the surface of the chassis may be highly undesirable or not even feasible.
It is thus apparent that there is a need in the art for an improved apparatus and/or method which solves the problems of the current art. There is a need in the art for one universal guide piece that may be secured to the interior of a chassis in multiple orientations so that electronic circuit cards may be inserted horizontally or vertically. There is also a need in the art for a plastic guide that does not require access to the exterior surfaces of the chassis for installation, that does not require the use of rivets or other protrusions through the surface of the chassis, and does not require clearance on the outer surface for attachment devices. There is further need in the art for a plastic guide that is easily installed and removed, that is not damaged in the removal process so that the plastic guide can be used over and over again, and that does not require the use of any special tools for installation or removal. There is a still further need in the art for a plastic guide that is not susceptible to breakage either from bumping or scraping of exterior protruding attachment devices or stress in the attachment device itself and that can be located in an interior corner offset without protrusions. The present invention meets these and other needs in the art.